mates of production of the three large | Townsite, City of Cobalt and Cobalt companies of Juneau, Alaska. A total production of 12,000,000 tons yearly is contemplated, yielding about $18,000,000. At present only the plant of the Alaska Gastineau has started, and only one unit of that mill is in operation. The production of the district will be materially increased in 1916. The Iditarod dredge of the Yukon Gold Co. has averaged more than $1.47 per cub. yd. since starting in 1912. Dredging in 1915 has occupied about the same relation to general gold mining as in former years. New dredging fields have not been discovered, with the exception of some areas in the Philippine Islands which have been proved profitable. As to new discoveries in the United States, the camp of Willard, named in honor of the fistic champion, has been opened in Nevada, and there seems to be some chance for its development into a profitable camp. Tonogold, also in Nevada, has not made much progress during the year, but cannot yet be called a failure. Rochester, the discovery of only a few years ago, is now on a permanent basis and is producing like a veteran. In Canada the discovery of payable gold at Kowkash, in Ontario, points to a widening of the profitable mining area in that already important province. In the Cobalt district, of Ontario, silver production has been kept up at a normal rate. The Mining Corporation of Canada, controlling the Lake properties, started a new annex to cyanide all the slimes from its mills. At Porcupine, the Hollinger has increased its milling capacity to 1,600 tons per day, and is treating, beside its own ores, a large tonnage from the Acme property, adjoining. The latter is fast becoming one of the great mines of Canada, which the Hollinger already is. In British Columbia there has been practically no change in the production or its details. A new claimant for honors in gold mining is the Eiderlinsky gold mine, near Eiderla, Russia, about 130 miles southeast of the Ural range. Gold and Silver Milling. The Knight-Christensen mill, at Silver City, Utah, was burned, the loss being $75,000, with no insurance; losses of this kind have fortunately been rare. The Rockland mill of the Pittsburg-Dolores Mining Co. completed its cyanide plant during the year and is now operating. The Elko Prince, at Elko, Nev., is building a cyanide-treatment mill using Dorr machinery principally. The old Virginia City camp continues about the same. The Mexican mill has been running throughout the year, but has had to call in some assistance in ore tonnage from outside mines. The mill of the Tomboy Company, near Telluride, Colo., has been completed. This is an important addition to the cyanide plants of the state and its operation will be watched with interest. LEAD H. O. HOFMAN The year 1915 has shown only one radical change in the treatment of lead ores. The war having stopped almost wholly scientific investigation of the metallurgical processes dealing with lead, the records deal mainly with descriptions and improvements of practice. Ore Purchasing. An interesting pamphlet by Prof. Charles H. Fulton entitled "The Buying and Selling of Ores and Metallurgical Products" is published by the Bureau of Mines (Tech. Paper 83). There are three general methods for buying lead ores. Payments are made (1) by the unit and at quotation, a system used chiefly in Colorado; (2) for 90 per cent. of the lead content at sales price with a deduction per pound, a system used chiefly in Utah, and (3) for 90 per cent. of the lead content at 90-95 per cent. of the sales price, a system used to some extent for Idaho ores. fire assay or the wet assay less 1-1.5 per cent forms the basis of valuation. The price in all three cases increases with the amount of lead in the ore; there are penalties for the presence of undesirable elements. The Owing to the high percentage of copper in the furnace charge, it is difficult to keep the lead wells open, consequently much of the time the lead is run out with the matte. It is separated in a rectangular settler which overflows into a circular oilfired matte settler. If the matte is sufficiently low in lead, it is converted directly for copper; otherwise it is cast, crushed, roasted and recharged into the furnace. When the lead wells are in working order, the lead is drossed at the furnace, but when the lead is obtained from the settler it is remelted and liquated in a small reverberatory furnace. Mechanical Ore Hearth.-The prob- | weeks. This leaves the briquettes lem of a satisfactory mechanical rab- hard and well suited for charging. bling device for the ore hearth has been solved by E. Newman at the works of the St. Louis Smelting and Refining Co. (Bull. Am. Inst. Min. Engrs., 1915, p. 2139.) With suitable ore, the ore hearth can be operated at less cost per ton of lead produced than the blast furnace, but working conditions are severe and unsanitary, owing to the requirement of almost continuous hand rabbling and exposure to fumes. The device designed by Mr. Newman imitates very closely the motions of hand rabbling; the results obtained have been entirely satisfactory. The length of the furnace, formerly limited to five feet, has been increased to eight feet without loss in efficiency; in fact the results obtained exceed expectations. Smelting Plants.-The lead-smelting practice at the El Paso (Texas) smelting works has been described by H. F. Easter (ibid., p. 1493). The smeltery is operated strictly on a custom basis; the source of ore supply is New Mexico, Arizona, western Texas and northern Mexico. The supply in recent years has been uncertain, and has shown a tendency toward excess in Si0, and a corresponding shortage of iron. The latter difficulty has been met by using roasted leady copper matte and converter slag from neighboring smelteries as fluxes. Unfortunately the introduction of copper from these sources has complicated the smelting practice. A crew of four men is usually required for unloading a car. Sampling is carried on first at the car by the shovelers, who reserve one tenth of the fines and lay aside lumps over 6 in. in diameter to be crushed and then sampled mechanically in Vezin machines. The sulphide ores are roasted in Godfrey mechanical roasters. The best results are obtained with a mixture of ore and leady copper matte. A furnace has a capacity of 30 tons in 24 hours; it reduces the sulphur content to 10-12 per cent. The roasted ore goes to eight Huntington-Heberlein pots which have a total capacity of 100 tons in 24 hours. The flue dust produced is briquetted with 10 per cent. of burned lime and dried for from three to six The Salida smeltery has been described by F. D. Weeks (ibid., p. 1691). The ore is rough-roasted in Godfrey and Wedge furnaces and sintered in Dwight-Lloyd machines. The plant was one of the first to install a Dwight-Lloyd equipment. The prod uct from the Godfrey and Wedge furnaces falls onto the center of a revolving cast-iron table where it is sprayed with water and discharged at the edge by fixed plows. This keeps down the dust and supplies the product with the required moisture for treating in the sintering machines. An improvement in the first installation of Dwight-Lloyd machines has been made by placing an adjustable rail by the side of the pallets. This rail carries the weight of pallets and prevents excessive wear and consequent leakage when the pallets are drawn across the top of the wind box. In order to eliminate the personal equation on the part of the assayers, the small bullets of lead bullion obtained by dip-sampling, each weighing about one-half assay ton, are weighed without trimming and cupelled. The results of the assays are not calculated by the assayer; the weights are reported as obtained, and changed into ounces per ton in the office. Parkes Process.-The compositions of the compounds formed in the Parkes process, the best procedure for obtaining a crust containing a minimum of lead, the reduction of loss to a minimum of metal, still form a field for research. Some light has been thrown on the subject by the ex- | Alice Hamilton; the results obtained periments of F. C. Newton (ibid., pp. are summarized in Mineral Industry 473-77). With the idea that the for 1914 (xxiii, 493). It is found that compound Zn,Ag, freezing at 665° in the United States, out of 7,400 men C., might be skimmed from the employed in 1912 in 19 plants, 1,769 lead, the zinc for desilverization men suffered from lead poisoning, was added at 705° C., and suc- while of 2,400 men in England only cessive skimmings were made as 56 were affected. The difference is the temperature fell to 345° C. The due to the laws enacted in England crusts obtained at the higher tem- and their proper enforcement. Lead peratures were distinctly poorer in poisoning has been shown to be caused silver than those removed at tempera- mainly by dust and smoke entering tures around 535°, the usual skim- through the mouth and nose, and not, ming temperature. With tempera- as formerly supposed, by absorption tures lower than 535°, considerable through the skin. Poisoning was lead was removed with the crust. The found to be most prevalent in orehigh temperatures increased the losses hearth plants. In blast-furnace of zinc and lead by oxidation, short- plants most of the poisoning occurred ened the life of the kettles and made on the tapping floor. Converting lead the work around the kettles more matte causes about as much poisonsevere. It is probable that the coming as ore-hearth work. Dwightpound Zn,Ag, dissolves in the lead Lloyd sintering causes less poisoning and does not freeze at its melting than pot-roasting. Men handling ores point of 665°. and by-products are frequently affectFume Condensation.-"Metallurgi- ed by lead. cal Smoke" is the subject of a paper by Prof. Charles H. Fulton published by the Bureau of Mines (Bull. 84). It discusses the various methods for precipitating fume and dust in use at copper and lead plants, gives tabulated analyses of fume and flue dust, and furnishes a bibliography of the subject. The smoke problem has also been discussed by F. G. Cottrell (Mineral Industry, xxiii, 867) with special reference to the development and success of the Cottrell method of electric precipitation (see also Copper, supra). Lead Poisoning.-Lead poisoning at smelteries has been investigated by The same author discusses lead poisoning in storage-battery factories. In some of the processes involved, lead fume, lead dust and oxide dust are produced, all of which are conducive to lead poisoning. In 1912 the cases of poisoning in storage battery plants in Germany formed 0.97 per cent. of the men employed; in Great Britain, 3 per cent.; in the United States, in the five largest factories, 17.9 per cent. Existing laws should be enforced, compelling the manufacturers to instal hoods, exhausts, etc., and to provide proper washing facilities. ZINC W. R. INGALLS Foreign Markets. It was foreseen in 1914 that the isolation of the German and Belgian zinc smelters, depriving Great Britain, France and Russia of the larger part of their normal supply of spelter and causing them to turn to the United States, was going to have extraordinary industrial and commercial effects, but nobody imagined that they would be so marvellous as the event. By the German capture of all the smelteries of Belgium and Poland and the works in the north of France, the mining companies of Broken Hill, New South Wales, which had sold nearly all of their ore to Belgian and German smelters were deprived of their mar ket. Great Britain thus found herself amply supplied with ore but nearly destitute of spelter for lack of smelting capacity. Certain of the Australian interests made plans for building new smelting works, but the German firms to whom the ore was contracted intervened and the matter passed into the courts and a decision releasing the mining companies was not rendered until late in the year. One company had previously cut the was at all times an excessive supply of zinc ore, but during the first three quarters of 1915 there was a deficiency in smelting capacity. The high prices paid for spelter represented a premium upon the use of smelting capacity, not a scarcity of ore. The extraordinary profit realized in zinc smelting had the natural result of stimulating production, which was done more quickly than anybody con (see Gordian knot by selling ore to Ameri- spelter. Charges were freely made by can smelters, assuming all risks, but zinc miners that the ore market was this was not done early enough to being manipulated against them by prevent a bad situation from aris- the smelters; the state of Missouri ing. In the meanwhile the British was led to make an investigation, zinc smelters had done practically and the U. S. Department of Justice nothing to relieve their country's ne- inaugurated an inquiry to find out if cessity. the smelters were operating in contraCommercial Conditions.-The pub-vention of the Sherman law. There lication of the American statistics early in January, which showed that the unsold stock of spelter had been reduced to less than 20,000 tons, started a buying movement which lifted the price by leaps and bounds. At the beginning of 1915 the price was 5.40 cents, basis St. Louis; at the beginning of March it was 10 cents, a figure never previously recorded. During March the price receded to about eight cents, and it was the gen-ceived to be possible. Furnaces were eral opinion among experts that it would gradually fall. On the contrary, an enormous demand by ammunition manufacturers (see also Iron and Steel, supra), developing early in April, started the market upward and within a relatively few weeks 25 cents per lb. was realized for prime western spelter. Brass special and intermediate spelters commanded abnormal premiums, while high-grade spelter fetched 40 cents per pound. The phenomenal price for spelter paralyzed the consumption of zinc for domestic peaceful purposes, especially the consumption of galvanized iron and steel; in many wares wherein zinc was formerly an element, substitutes were used and fortunately a good many substitutes were available. Indiscreet buying by new figures in the market, narrow military specifications, sharp manipulations by sellers, were factors in this extraordinary market. The inwardness of the situation was, however, that in the exhaustion of stocks the market had lost its balance wheel, while there was a prospective requirement for spelter greater than American producers could supply if all buyers were to be satisfied. Late in the summer the price for spelter declined to 10-11 cents per pound, but it rallied later to 16-18 cents. During this time the producers of zinc ore were much dissatisfied owing to the failure of the raw product to rise in the same proportion as added quickly to existing plants, idle High-Grade Spelter.-Previous to the war there was a relatively small demand for high-grade spelter (99.9 per cent. zinc) and intermediate spelter (99.5 to 99.9 per cent. zinc). The military demand for spelter focused especially upon those grades, which are required in the manufacture of cartridge brass. The single producer of high-grade spelter, strictly speaking, was able to exact whatever price he pleased. Other producers were led to manufacture intermediate spelter, either by the smelting of selected ore, or by the redistillation of common spelter. The latter was practiced on a large scale. Ore Supply.-Ore from foreign countries was brought to the United States in large quantities in 1915, coming from countries whence none had been received heretofore. A large the Steel Corporation is the largest consumer of spelter in the United States, and the spelter market heretofore has been to a large extent governed by whether this corporation was buying or not, this new industrial development will be of farreaching importance. tonnage of Australian ore was immensely increased. Inasmuch as brought, ships being chartered to fetch it by way of the Panama Canal and deliver it at Mobile. The blockade of the Panama Canal in October compelled several of these ships to round Cape Horn. American smelters are able to purchase this ore at relatively low figures, there being no other market for it. The supply of ore was further increased by the expanding use of the flotation process (see Mining and Ore Dressing, supra), while the high prices for ore, even if not so high as for spelter, stimulated production in all quarters. The supply of ore became so excessive that during periods of the year producers found difficulty in finding buyers for it on any terms. Technical Progress.-The chief metallurgical feature of 1915 was the establishment of an electrometallurgy of zinc. The production of electrolytic spelter was actually begun by the Anaconda Copper Mining Co. at Anaconda, Mont., by the Weedon Mining Co. at Welland, Ont., and by the Consolidated Mining and Smelting Co. at Trail, B. C., while other concerns carried on experimental work and will probably soon begin the produc tion of this kind of spelter. This branch of metallurgy has heretofore failed to develop owing to the relatively high cost of producing spelter electrically, but with the conditions existing in 1915, nothing short of a preposterous cost could be too high to permit a profit. It is possible that the manufacture of electrolytic spelter having been begun under such favorable auspices, improvements will be invented which will permit the production of spelter in this way to be carried on under normal conditions. New Smelters.-Among the new plants laid down in 1915 was an immense plant at Donora, Pa., by the U.S. Steel Corporation, which, when completed, will have capacity for producing 40,000 tons of spelter per annum and will be the largest single zinc smeltery in the world. Previous to the war 18 months would have been reckoned as a reasonable time for the construction of such a plant. By working night and day and concentrating its whole construction force upon this plant, the company succeeded in producing spelter on Oct. 21, just four months and ten days after the begin- The other important metallurgical ning of construction. The Steel Cor- novelty of 1915 was the refining of poration was previously engaged in crude spelter by redistillation (fracthe zinc-smelting business, having tional distillation) on a large scale. plants at Cherryvale, Kans., and St. The extraordinary premium paid for Louis, but with the addition of Do-high-grade intermediate spelter rennora its production of spelter will be dered this a profitable operation. STATISTICS OF MINERAL PRODUCTION |